Which of the following compounds will absorb the maximum quantity of heat when dissolved in the same amount of water? The heats of solution of these compounds at $25 \, ^\circ C$ in $kJ/mole$ of each solute are given in brackets.

Compounds with high heat of formation are less stable because

Consider the reactions:
$C_{(s)} + 2H_{2(g)} \to CH_{4(g)}, \Delta H = -x \ kcal$
$C_{(g)} + 4H_{(g)} \to CH_{4(g)}, \Delta H = -x_1 \ kcal$
$CH_{4(g)} \to CH_{3(g)} + H_{(g)}, \Delta H = +y \ kcal$
The bond energy of $C-H$ bond is:

The standard enthalpy of formation of carbon monoxide at $298 \ K$ is $-110.5 \ kJ/mol$. The standard internal energy of formation of carbon monoxide at $298 \ K$ and constant volume is ............... $kJ/mol$. (in $.73$)

Which of the following pairs has a heat of neutralisation equal to $13.7 \, Kcal$?

Combustion of $1$ $mol$ of benzene is expressed as:
$C_6H_{6(l)} + \frac{15}{2} O_{2(g)} \rightarrow 6CO_{2(g)} + 3H_2O_{(l)}$
The standard enthalpy of combustion of $2$ $mol$ of benzene is $-x$ $kJ$.
$x = . . . . . . . . . .$
$(1)$ Standard enthalpy of formation of $1$ $mol$ of $C_6H_{6(l)}$ is $48.5$ $kJ \ mol^{-1}$.
$(2)$ Standard enthalpy of formation of $1$ $mol$ of $CO_{2(g)}$ is $-393.5$ $kJ \ mol^{-1}$.
$(3)$ Standard enthalpy of formation of $1$ $mol$ of $H_2O_{(l)}$ is $-286$ $kJ \ mol^{-1}$.